Katy Perry has reflected on the moment in which she knew her marriage was doomed, though had to perform for fans just minutes later. The singer - whose new 3-D concert movie also documents her divorce from Russell Brand - says she broke down in tears moments before going on stage.The Fireworks singer explained to the Hollywood Reporter about one particular scene in the movie, which shows the clearly distressed singer preparing for a show backstage. At the time, she was going through problems in her marriage, and said, "What was going on in my personal life was so overwhelming that I had to bend over to let those tears fall straight out of my eye sockets and not my false lashes just as I'm about to go up on that ramp and sing Teenage Dream", she added, "I had to smack myself across the face and say, These problems are my problems, they are not my audience's problems, learn to separate that". Katy and Russell's relationship was constantly under the media spotlight, after they met at the MTV Video Music Awards in September 2009. They married in India in October 2010, though split just 14 months later. The 27-year-old singer admitted the film includes scenes that two years ago she "wouldn't feel completely comfortable with people seeing". Russell is reported to have wanted the personal footage removed from the film, though studio bosses were understandably keen to keep it in.